The photographer is in over her head. She owns her photo, but she doesn't own the "idea" of the back of Rod Stewart's head. Not even Rod Stewart owns that "idea."
And while we can't just copy her photo, we can take another photo that expresses the same idea (Stewart's head). And since there aren't that many way to photograph Rod Stewart's rear-dome, the photos would have to be essentially identical for any copyright infringement. The photos here are not identical: the light is different, the hair is messed up differently... it looks like a losing case.